Lock for preserve cans and other containers and a method of making it

ABSTRACT

A lock for package containers, for example, preserve cans and tins, has a closed elastic cordlike ring located between the edge of the container and the edge of the cover and serving simultaneously for sealing and opening. To open the container, the ring is pulled by a strap carried by the ring out of the passage between the cover and the body of the container. The lock is particularly characterized in that this ring is brought into the sealing space formed between the edges of the container and cover in a liquid or plastic state and is hardened on location.

United States Patent [72] Inventor Hans-Joachim Bluhm Weddel. Germany [21] Appl. No. 801,226

[22] Filed Jan. 30. 1969 [45] Patented Sept. 14, 1971 [73] Assignee Schmalbach-Lubeca-Werke AG Brauschweig, Germany [32] Priority Feb. 15, 1968 [33] Germany [54] LOCK FOR PRESERVE CANS AND OTHER CONTAINERS AND A METHOD OF MAKING IT Primary Examiner-Theron E. Condon Assistant Examinerl*lorace M. Culver Attorney-Richards & Geier ABSTRACT: A lock for package containers, for example, preserve cans and tins, has a closed elastic cordlike ring located between the edge of the container and the edge of the cover and serving simultaneously for sealing and opening. To open the container, the ring is pulled by a strap carried by the ring out of the passage between the cover and the body of the container. The lock is particularly characterized in that this ring is brought into the sealing space formed between the edges of the container and cover in a liquid or plastic state and is hardened on location.

LOCK FOR PRESERVE CANS AND OTHER CONTAINERS AND A METHOD OF MAKING IT This invention relates to a lock for preserve cans and other containers and to a method of making it. The invention refers more particularly to a lock consisting of a closed elastic cordlike ring located between the edge of a containerand the edge of its cover andserving simultaneously as a sealing ring and an opening ring, the container being opened by pulling the ring by a strap attached thereto out of a passage between the cover and the body of the container.

Contained locks of this type are known in the art. As compared to conventional locks of preserve cans with folded covers, they have, among others, the advantage that they can be easily opened without the use of any opening tools. To open the container, it is merely necessary to pull the strap of the ring in an inclined downward direction. Then the ring is separated from its clamping seat through the passage between the cover and the body of the container, so that the cover can be easily removed. Beside this very advantageous, easy opening procedure, a further advantage of containers of this type consists in that the entire upper surface of the filling is completely opened, so that, for example, the container can be.

easily emptied by turning it upside down.

The closed sealing and opening ring used up to now in these containers consisted of a single member usually made, of

elastic rubber; it was initially made individually and later in.

larger numbers by a special rubber making and finishing a process.

This separate manufacture by itself increased the costs of the container. However, the main drawback connected with,

these rings lies in their mounting to produce a finished container. For example, it was found that a substantial effort was required to mount the ring which must be placed under lighttension upon the container body or the cover. The original. mounting by hand was too expensive and did not produce the high piece output necessary for mass production. The use of the so-called ring-applying machine eliminated the high labor costs. However, this machine is also very costly, too complicated in its construction and too expensive in its use. Furthermore the machine cannot operate with an output compatible with a rational container manufacture.

When mounting the rings it is necessary to take intoconsideration. numerous details which are of importance to provide a secure locking of the container. These details can be hardly taken into consideration when the ring is mounted by a machine or they can be effected only by the use of additional devices. For example, the twisting of the ring must be avoided.

Furthermore, when using the closing process in known constructions of these container locks, care must be taken that the applied ring will not deflect during the closing. This requires either the use of additional devices, such as supporting holders, or additional manipulations at the container itself, or the additional operation of firmly clamping the ring within the range of the cover end.

The wholesale output of the containers with large number of pieces has been made doubtful for the above-stated reasons despite the good and variable applicationpossibilities of these containers in numerous branches and their easy manner of opening.

An object of the present invention is to overcome these drawbacks.

Considerations as to how these drawbackscould be overcome were directed to the sealing and tear-off ring which doubtless presented the major problem. After lengthy experimentations, the subject of the present invention was discovered, namely, that the sealing and opening ring should be brought into the sealing space formed between the edges of the container and cover in a liquid or plastic state and hardened on location; this provides not only a rational manufacture of these cans, but also greatly improves the sealing as well as various other properties, such as a diminution of the tearing forces and an increase in the resistance to rupture.

This procedure eliminates all above-described drawbacks taking place during the mounting. The container itself is made not only cheaper, but is rendered more reliable as far as its structure is concerned.

In accordance with a further development of the present in vention, the sealing space provided for the seal is formed on the one hand by the end of the container body provided with an outer roll and, on the other hand, by the cover end extending in a curve over the outer roll and having an edge surface bent in the direction toward the container body. Thusthe sealing space is advantageously shaped as a ring channel and is well suited for receiving the liquid or plastic sealing mass.

A further feature of the present invention consists in that the end of the cover can be shaped as a practically closed roll. This provides a greater resistance to rupture, thereby generally improving the safety of the container closure. This roll can be made either before introducing the sealing mass or after its introduction,'although the first-mentioned procedure is preferred.

According to a further feature of the present invention the cover end is provided with a preliminary gumming. Such gumming isnecessary in several cases and has the advantage when for example, a thinly liquid sealing mass is used, of

preventing the sealing mass after it has been poured, from running along an inner wall of the container, with the danger that the interior of the container will be dirtied. To provide a better closure'for the container after it has been opened, the gumming should be then separated from the ring and should remain upon the end of the cover.

According to a further feature of the present invention, the cover edge has a recess close to the pulling strap in order to diminish the tearing forces while the container is being opened.

The present invention provides a particularly advantageous, simple and effective-process for mass production, especially for the container-making industry, for making and introducing sealing and opening rings provided with pulling straps into the containers. According to this process the container with the cover firmly pressed into it is turned upside down to the extent of whereupon the liquid or plastic mass forming the ring is poured into the now-opened sealing space; then the pulling strap, made of the same material and already hardened or preliminarily hardened, is introduced as a separate part into the mass which is still liquid or plastic and then the ring and the strap are jointly hardened. This process requires a minimum of operating devices. The sealing space shaped as a ring channel can receive the sealing mass, for example by spraying, by devices generally used in the package industry.

According to a further feature of the present invention, the strap can be attac ed to the container body, for example, by gluing, to make certain that the strap will be located in the correct position upon the sealing ring after the hardening and to avoid the use of special holding devices. This takes place preferably immediately after the making of the container body and before the cover is applied thereto, whereby care must be exerted that the free end of the strap should be long enough and should project sufficiently into the sealing space.

The attachment or gluing should preferably consist of a dot so that the strap can be easily pulled off when opening the container.

According to another feature of the present invention, the liquid or plastic mass forming the ring can be provided with foam-producing additives, for example, means for improving the swelling and thus the shape following sealing. As already stated, the mass can be sprayed or poured into the sealing space or introduced in any other suitable manner. Depending upon requirements the mass can consist of rubber, India rubber or a plastic material. The manner in which the mass is introduced will depend upon the specific properties of the mass being used.

According to a further feature of the present invention, after the sealing mass has been introduced and hardened the lock can finally be completed and perfected by bending the edge surface of cover end radially and inwardly toward the container body, so as to form a passage.

To sum up, a package container of the described type which is thus produced, combines the advantages of an easy opening possibility without the use of tools with a simplified and cheaper manufacture. The new type of the sealing and opening member has also additional above-described advantages over the prior ones.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing, by way of example only, preferred embodiments of the inventive idea.

In the drawings:

FIG. 1 is a section through an upper portion of a container provided with a closure of the present invention on a greatly enlarged scale;

FIG. 2 is similar to FIG. 1 but shows a somewhat different construction;

FIG. 3 is a partial side view of a container provided with the closure of the present invention;

FIGS. 4a to 4f are partial sectional views illustrating the most important process steps of the present invention for producing and applying a sealing and opening ring provided with a strap and shown as the closures of FIGS. 1 and 2;

FIGS. 5a to 5c are side views showing different types of straps.

The drawings show a package container having a body 1 which is preferably made of sheet metal. The upper free end of the container 1 is bent to form an outer roll 2.

The closure for the container consists of a cover 3 having a bottom portion 4 which lies somewhat deep within the container. The bottom 4 goes over into vertical or substantially vertical sides 5 terminating in edge surfaces 6 which extend archlike over the outer roll 2 of the body 1. Thus a sealing space 7 is formed which is used for receiving a ring 8 serving as a sealing and, at the same time, as an opening ring. This ring 8 is introduced into the sealing space 7 in liquid or plastic state and is hardened on location.

The drawings show a pulling strap 9 by means of which the ring 8 can be pulled out of the passage 10 between the cover and the container body. In the embodiments shown in FIG. 1, 2, 3 and 4 the strap consists of a tongue-shaped part. However, according to the present invention, the strap 9 can also have another shape, for example, it can be shaped as a ring. The ring shape facilitates the use and thus the application of a greater pulling force (FIGS. 5b and 5c).

To increase resistance against rupture, the edge surface 6 of the cover 3 also has-at its end a nearly closed roll 11 (FIG. I).

To make easier the removal of the ring 8 through the passage I0, the edge 6 of the cover can be provided with a recess 15 close to the strap 9, as illustrated in FIG. 3.

The embodiment of the container according to FIG. 2 differs from that of FIG. I in that, according to FIG. 2, a layer of gumming 12 is located upon the inner surface of the curved portion of the edge surface 6. This layer of gumming can be applied directly after the cover 3 has been made; the layer is necessary and is used when a more or less thinly liquid mass is used for the ring 8. The purpose of the layer of gumming 12 is to prevent the thinly liquid mass to penetrate, for example, by capillary action prior to its hardening into the space between the outer roll 2 of the container body I and the side 5 of the cover 3, whereby it could possibly penetrate into the interior of the container and dirty it. On the other hand, a thinly liquid sealing mass has the advantage that the sealing is better effected and that the elasticity is better.

When the mass for the ring 8 consists of a plastic or viscous mass, the use of the layer of gumming upon the cover is not necessary, since the mass does not flow that fast.

The construction of FIG. 2 also differs from the construction of FIG. I in that in the construction of FIG. 2 the edge surface 6 of the cover is not shaped as a nearly closed roll but terminates in a slightly bent edge I la. (The roll It is shown by broken lines in FIG. 2 for the sake of comparison.).

Practical experience has shown that both constructions of the ends of the edge surfaces 6, as shown in FIGS. I and 2 are suitable. However, the construction of FIG. I having a nearly closed roll 11 at the end of the edge surface 6, is to be preferred since it provides a better resistance against rupture.

The nearly closed roll of FIG. 1 or the partial roll lla of FIG. 2 can be provided selectively either immediately after the making of the cover 3 or later on after the ring 8 has been introduced and hardened.

The process of making and inserting the sealing and opening ring 8 is carried out as follows, as illustrated in FIGS. 4a to 4f:

The cover 3 can be provided with a layer of gumming 12, as shown in FIG. 4a" or be devoid of this layer, as shown in FIG. 4a, depending upon the consistency of the mass for the ring 8. The cover can be provided at the end of its edge surface with a nearly closed roll 11 or with a partially bent edge 11a. The cover is pressed into the container 1 (FIG. 4b). Then the outer roll 2 of the container 1.will move into the sealing space 7, as shown in FIG. 40. Ifa layer of gumming 12 is provided in the cover 3, the outer roll 2 of the container 1 will engage the gumming l2 and will compress it somewhat, depending upon the consistency of the gumming (FIG. 4c).

Then the container and the cover are turned upside down to the extent of as shown in FIG. 4d. The sealing space is then open from the top and thus forms a receiving space having the shape ofa ring channel. However, for the sake of easier manufacture, particularly in the case of mass production, the two above-described steps will be preferably carried out immediately after the manufacture of the two parts, namely the container base 1 and the cover 3, by initially placing the cover 3 into the position shown in FIG. 4d and then inserting the container 1 in an upside down position into the cover 3. Obviously this procedure, differing somewhat from the one initially described, is also included within the scope of the present invention. The last-mentioned two steps of this procedure have the advantage that the previously described turning or rotation to the extent of 180 is avoided.

Then the mass which will form the elastic sealing and opening ring 8 will be poured in liquid or plastic state into the ringlike channellike sealing space 7 which is now open at the top. In the diagrammatic illustration of FIG. 4d, a spraying nozzle 13 is shown by means of which the mass is sprayed. However, in accordance with the present invention, the mass can be also poured into this space or introduced by any other suitable means. The device used for this purpose may consist of spraying devices generally used in the packing industry. Practical experience has shown that when round containers are used, it is particularly advantageous to provide a rotation of the con tainer body and the cover under a single nozzle while it sprays the mass. However, obviously it is also within the scope of the present invention to provide several nozzles and to rotate them around the container body and the cover which stand still.

When the container bodies and covers are not round, it is advisable to spray the mass, for example, by several nozzles which are correspondingly divided around the body, while the body and the cover stand still. However, in that case it is also possible to use one or several rotating nozzles. It is also possible to rotate the container with the cover and to use one or more radially steered nozzles. While such variations are known per se, they must be also included within the scope of the present invention.

The mass used for making the ring may consist of rubber, India rubber or plastic materials, depending upon the requirements placed on the lock and the properties of the mass. It may be advisable to provide the mass with additives which will produce foaming, for example, fuel drive means, to provide a blowing up of the mass and thus provide better sealing with best possible filling of the space.

Immediately after the introduction of the mass for the formation of the ring 8, the strap 9 of the same previously hardened material is introduced as a separate part into the mass which is still liquid or plastic. This step is shown in FIG.

4e. However, it is also possible in accordance with the present invention to removably attach, for example, by gluing, the strap to the container body 1 immediately after the container body I has been made. This would be the best procedure for the mass production of such containers. The glue spot is indicated by the numeral 14 in FIGS. 1 and 4e.

This attachment of the strap prior to the introduction of the liquid or plastic mass into the sealing space 7 provides a guarantee that the strap 9 will be in its proper location, namely, it will make certain that there is the correct chemical connection with the sprayed-in mass and will also provide a visually pleasant location.

FIGS. 50, 5b and 50 show different constructions of the gripping strap 9. According to FIG. 5a the flaplike strap 9 is connected with the ring 8 and is provided with transverse ribs 19 to facilitate holding. FIG. 5b shows a construction wherein the ring 8 is connected with a ring-shaped closed strap 9. In this case, the ring of the strap does not have to be closed; the strap can consist of one piece the ends of which are brought together to form a ring and are connected to the ring 8.

Finally, FIG. 50 shows a strap having the shape of a ring 9 but provided with an extending fiap 29 which is connected with the ring 8.

After the strap 9 has been introduced, it hardens along with the introduced sealing mass to form the sealing and opening ring 8, whereby there is an intensive connection of the material between the strap 9 and the ring 8, which is so firm that when the strap is pulled for the purpose of opening the container, the strap will not be separated from the ring 8.

After the mass forming the ring 8 has been introduced into the sealing space 7 and has been hardened, the process is continued by bending the edge surface 6 of the cover 3 toward the container, so that the passage 10 is formed. This step provides the final closing of the container.

The final shape of the container is shown again on a smaller scale in FIG. 4f, whereby in the described example the can is turned again to the extent of to place it in its correct position.

To open the container, it is merely necessary to separate the strap 9 from the glue location 14 which is preferably dot shaped. By pulling downwardly at an inclination the ring 8 can be pulled through the passage 10 and the cover 3 will be opened.

Preferably the above-described closure is completed by the package-making industry. The concern filling the containers will usually fill the cans from the bottom, since in that case its only procedure is to foldingly apply the bottom I claim:

1. A process of making a lock for a container having an outer roll-shaped top and a cover having curved edges, said process comprising placing said cover over said container top, whereby an annular space is formed between the roll-shaped top and the curved edges of the cover, inverting the assembled container and cover, pouring a sealing mass into said annular space in a liquid or plastic state, introducing a pulling strap into the liquid sealing mass, allowing said sealing mass to harden to form a sealing and opening ring for the container top and thereupon bending the edges of the cover toward the container to form a narrow annular passage between the bent edges of the cover and the adjacent surfaces of the container. 

1. A process of making a lock for a container having an outer roll-shaped top and a cover having curved edges, said process comprising placing said cover over said container top, whereby an annular space is formed between the roll-shaped top and the curved edges of the cover, inverting the assembled container and cover, pouring a sealing mass into said annular space in a liquid or plastic state, introducing a pulling strap into the liquid sealing mass, allowing said sealing mass to harden to form a sealing and opening ring for the container top and thereupon bending the edges of the cover toward the container to form a narrow annular passage between the bent edges of the cover and the adjacent surfaces of the container. 